Sheet feeding apparatus and sheet processing apparatus

Abstract

A sheet feeding apparatus has a pair of feeding roller and separating roller an inter-shaft distance changing mechanism for the pair of rollers, and sheet detecting means, and a sheet fed is rammed against the surface on which the feeding roller and the separating roller overlap each other to thereby correct skew feeding, and the feeding roller and the separating roller are moved away from each other to thereby feed the sheet. When the passage of the fed sheet between the feeding roller and the separating roller is detected the feeding roller and the separating roller assume a state in which sheet feeding is impossible. By the above-described operation being performed for each sheet, the correction of skew feeding and the separation of a sheet are effected by the feeding roller and the separating roller.

What is claimed is:  
     
       1. A sheet feeding apparatus having a sheet feeding rotatable member rotated in a forward feeding direction and a sheet separating rotatable member rotated in a reverse feeding direction, said sheet feeding rotatable member and said sheet separating rotatable member being disposed in opposed relationship with each other and rotated at the opposed portion, and separating and conveying sheets one by one between both said rotatable members, said sheet feeding apparatus comprising: 
       inter-shaft distance changing means for at least one of both said rotatable members to change the inter-shaft distance thereof relative to the other rotatable member;  
       sheet detecting means provided near both said rotatable members for detecting the passage of the sheets; and  
       means for controlling so that with the start of feeding, at least one of both said rotatable members may start the operation of spacing its inter-shaft distance relative to the other rotatable member, and when a sheet is detected by said sheet detecting means, the operation of spacing said inter-shaft distance may be stopped, and when the feeding of said sheet is completed, at least one of both said rotatable members may bring the inter-shaft distance thereof relative to the other rotatable member close to a position in which feeding is impossible.  
     
     
       2. A sheet feeding apparatus according to claim  1 , wherein said sheet feeding rotatable member and said sheet separating rotatable member are rollers, and the rotary shafts of said rollers are substantially parallel to each other and formed with comb-tooth-like grooves on the outer peripheral portions thereof, and have a shape in which the concave surfaces and convex surfaces of the grooves are in non-contact with each other and can overlap each other axially thereof. 
     
     
       3. A sheet feeding apparatus having a sheet feeding rotatable member rotated in a forward feeding direction and a sheet separating rotatable member rotated in a reverse feeding direction, said sheet feeding rotatable member and said sheet separating rotatable member being disposed in opposed relationship with each other and rotated at the opposed portion, and separating and conveying sheets one by one between both said rotatable members, said sheet feeding apparatus comprising: 
       inter-shaft distance changing means for at least one of both said rotatable members to change the inter-shaft distance thereof relative to the other rotatable member;  
       sheet detecting means provided near both said rotatable members, for detecting the passage of the sheets; and  
       means for controlling so that with the start of feeding, at least one of both said rotatable member may start the operation of spacing its inter-shaft distance relative to the other rotatable member, and may stop the operation of spacing said inter-shaft distance after the operation of spacing said inter-shaft distance has performed by a predetermined amount from a point of time at which a sheet has been detected by said sheet detecting means, and when the feeding of said sheet is completed, at least one of both said rotatable members may perform the operation of bringing the inter-shaft distance thereof relative to the other rotatable member close to a position in which feeding is impossible, for each sheet fed.  
     
     
       4. A sheet feeding apparatus according to claim  3 , wherein said sheet feeding rotatable member and said sheet separating rotatable member are rollers, and the rotary shafts of said rollers are substantially parallel to each other and formed with comb-tooth-like grooves on the outer peripheral portions thereof, and have a shape in which the concave surfaces and convex surfaces of the grooves are in non-contact with each other and can overlap each other axially thereof. 
     
     
       5. A sheet feeding apparatus according to any one of claims  1  to  4 , wherein said feeding rotatable member and said sheet separating rotatable member are in a state in which they hamper the feeding of the sheets before the feeding of the sheets is started or after the inter-shaft distance has been brought close. 
     
     
       6. A sheet feeding apparatus having a sheet feeding rotatable member rotated in a forward feeding direction and a sheet separating rotatable member rotated in a reverse feeding direction, said sheet feeding rotatable member and said sheet separating rotatable member being disposed in opposed relationship with each other and rotated at the opposed portion, and separating and conveying sheets one by one between both said rotatable members, said sheet feeding apparatus comprising; 
       inter-shaft distance changing means for at least one of both said rotatable members to change the inter-shaft distance thereof relative to the other rotatable member;  
       sheet detecting means provided downstream of the axially most proximate portions of both said rotatable members with respect to the direction of sheet conveyance; and  
       means for controlling so that with the start of feeding, at least one of both said rotatable members may start the operation of spacing its inter-shaft distance relative to the other rotatable member, and when the passage of a sheet through the most proximate portions of both said rotatable members is detected by said sheet detecting means, the operation of spacing said inter-shaft distance may be stopped, and the operation of at least one of both said rotatable members bringing the inter-shaft distance thereof relative to the other rotatable member close to a position in which feeding is impossible, on the basis of the sheet non-detection of said sheet detecting means, may be performed for each sheet fed.  
     
     
       7. A sheet feeding apparatus according to claim  6 , wherein said sheet feeding rotatable member and said sheet separating rotatable member are rollers, and the rotary shafts of said rollers are substantially parallel to each other and formed with comb-tooth-like grooves on the outer peripheral portions thereof, and have a shape in which the concave surfaces and convex surfaces of the grooves are in non-contact with each other and can overlap each other axially thereof. 
     
     
       8. A sheet feeding apparatus having a sheet feeding rotatable member rotated in a forward feeding direction and a sheet separating rotatable member rotated in a reverse feeding direction, said sheet feeding rotatable member and said sheet separating rotatable member being disposed in opposed relationship with each other and rotated at the opposed portion, and separating and conveying sheets one by one between both said rotatable members, said sheet feeding apparatus comprising: 
       inter-shaft distance changing means for at least one of both said rotatable members to change the inter-shaft distance thereof relative to the other rotatable member;  
       sheet detecting means provided downstream of the axially most proximate portions of both said rotatable members with respect to the direction of sheet conveyance; and  
       means for controlling so that with the start of feeding, at least one of both said rotatable members may start the operation of spacing its inter-shaft distance relative to the other rotatable member, and when the passage of a sheet through said most proximate portions is detected by said sheet detecting means, the operation of spacing said inter-shaft distance may be stopped after the operation of spacing said inter-shaft distance by a predetermined amount has been performed from the point of time of the detection, and the operation of at least one of both said rotatable members bringing the inter-shaft distance relative to the other rotatable member close to a position in which sheet feeding is impossible, on the basis of the sheet non-detection of said sheet detecting means, may be performed for each sheet fed.  
     
     
       9. A sheet feeding apparatus according to claim  8 , wherein said sheet feeding rotatable member and said sheet separating rotatable member are rollers, and the rotary shafts of said rollers are substantially parallel to each other and formed with comb-tooth-like grooves on the outer peripheral portions thereof, and have a shape in which the concave surfaces and convex surfaces of the grooves are in non-contact with each other and can overlap each other axially thereof. 
     
     
       10. A sheet feeding apparatus according to any one of claims  6  to  9 , wherein said sheet feeding rotatable member and said sheet separating rotatable member are in a state in which they hamper the feeding of the sheets before the feeding of the sheets is started or after the inter-shaft distance has been brought close. 
     
     
       11. A sheet processing apparatus having: 
       a supporting portion supporting a bundle of sheets thereon;  
       a feeding rotatable member rotated in a direction to feed the sheets fed from said supporting portion;  
       a separating rotatable member disposed in opposed relationship with said feeding rotatable member and rotated in a direction opposed to said feeding direction;  
       first sheet detecting means disposed near the sheet entrance of both said rotatable members;  
       second sheet detecting means disposed near the sheet exit of both said rotatable members;  
       changing means for moving the rotary shafts of both said rotatable members toward and away from each other to thereby change the distance between both said rotatable members;  
       means for controlling said changing means so that the rotary shafts of said rotatable members may be moved in a direction to widen the spacing therebetween by the sheet detection of said first sheet detecting means, and then the movement of the rotary shafts of both said rotatable members may be stopped at a predetermined position by the sheet detection of said second sheet detecting means; and  
       processing means for processing the sheets fed by said feeding rotatable member.  
     
     
       12. A sheet processing apparatus according to claim  11 , wherein said control means controls so that when said second sheet detecting means has come to detect no sheet after it has detected the sheet, the rotary shafts of both said rotatable members may be moved in a direction to narrow the spacing therebetween, and when the spacing has reached a set spacing, the movement may be stopped. 
     
     
       13. A sheet processing apparatus according to claim  11 , wherein said control means performs the operation of controlling said spacing each time a sheet is fed. 
     
     
       14. A sheet processing apparatus according to claim  11 , wherein said feeding rotatable member has large-diametered portions and small-diametered portions alternately in the axial direction of the rotary shaft thereof, said separating rotatable member has large-diametered portions and small-diametered portions alternately in the axial direction of the rotary shaft thereof, and both said rotatable members are disposed so that the large-diametered portions and the small-diametered portions thereof may be opposed to each other. 
     
     
       15. A sheet processing apparatus according to claim  14 , wherein both said rotatable members are disposed with the large-diametered portions thereof overlapping each other so that the large-diametered portions of one of both said rotatable members may come into the small-diametered portions of the other rotatable member. 
     
     
       16. A sheet processing apparatus according to claim  14 , wherein said processing means includes means for reading images on the sheets. 
     
     
       17. A sheet feeding apparatus having a sheet feeding rotatable member rotated in a forward feeding direction and a sheet separating rotatable member rotated in a reverse feeding direction, said sheet feeding rotatable member and said sheet separating rotatable member being disposed in opposed relationship with each other, and separating and conveying sheets one by one between both said rotatable members, said sheet feeding apparatus comprising: 
       shaft distance changing means for changing a distance between a shaft of said sheet feeding rotatable member and a shaft of said sheet separating rotatable member;  
       sheet detecting means for detecting the sheet conveyed by both said rotatable members; and  
       means for controlling the shaft distance changing means so that with the start of feeding, the distance of the shafts of both said rotatable members is widened from a close condition in which sheet feeding is impossible, and the operation of said shaft distance changing means is stopped according to detection of a sheet passed between said rotatable members by said sheet detecting means, and when the feeding of said sheet is completed, said shaft distance changing means returns the shaft of both said rotatable members to the close condition.  
     
     
       18. A sheet feeding apparatus according to claim  17 , wherein said shaft changing means moves at least one of both said rotatable members. 
     
     
       19. A sheet feeding apparatus according to claim  18 , wherein each of said sheet feeding rotatable member and said sheet separating rotatable member have the shaft and a roller, and said rollers formed with comb-tooth-like grooves on the outer peripheral portions thereof, and have a shape in which the concave surface and convex surface of the grooves are in non-contact with each other and can overlap each other axially thereof. 
     
     
       20. A sheet feeding apparatus according to claim  19 , wherein said feeding rotatable member and said sheet separating rotatable member are in a state in which they regulates a leading end of the sheet when the feeding of the sheet starts. 
     
     
       21. A sheet feeding apparatus according to claim  17 , wherein said sheet detecting means is a sensor disposed downstream of said rotatable members and said controlling means controls said shaft distance changing means so as to stop the movement of said shafts according to the detection of the sheet by said sensor. 
     
     
       22. A sheet feeding apparatus according to claim  21 , wherein said controlling means controls said shaft distance changing means so as to return the shafts to the close condition according to detection of the sheet by said sensor. 
     
     
       23. A sheet feeding apparatus according to claim  17 , further comprising sheet supporting means for supporting the sheets and sheet supply means for feeding out the sheet from said sheet supporting means, wherein said sheet detecting means has a first sensor disposed downstream of said rotatable members and a second sensor disposed upstream of said rotatable members and said controlling means controls said shaft distance changing means so as to start to widen the distance of said shafts according to the detection of the sheet by said second sensor and to stop the movement of said shafts according to the detection of the sheet by said first sensor. 
     
     
       24. A sheet feeding apparatus according to claim  23 , wherein said controlling means controls said shaft distance changing means so as to return the shaft to the close condition according to detection of the sheet by said first sensor. 
     
     
       25. A sheet processing apparatus having a sheet feeding rotatable member rotated in a forward feeding direction and a sheet separating rotatable member rotated in a reverse feeding direction, said sheet feeding rotatable member and said sheet separating rotatable member being disposed in opposed relationship with each other, and separating and conveying sheets one by one between both said rotatable members, said sheet processing apparatus comprising: 
       shaft distance changing means for changing a distance between a shaft of said sheet feeding rotatable member and a shaft of said sheet separating rotatable member;  
       sheet detecting means for detecting the sheet conveyed by both said rotatable members;  
       means for controlling the shaft distance changing means so that with the start of feeding, the distance of the shafts of both said rotatable members is widened from a close condition in which sheet feeding is impossible, and the operation of said shaft distance changing means is stopped according to detection of a sheet passed between said rotatable members by said sheet detecting means, and when the feeding of said sheet is completed, said shaft distance changing means returns the shaft of both said rotatable members to the close condition; and  
       processing means for processing the sheets fed by said rotatable members.